Redundant power distribution circuits for electric vehicles

ABSTRACT

An electrically powered vehicle comprises a DC bus and a plurality of batteries, each coupled in parallel to the DC bus. At least one switch is coupled in series between at least one battery of the plurality of batteries and the DC bus and a plurality of inverter circuits are each coupled in parallel to the DC bus. A plurality of motors are each coupled to a respective inverter circuit of the plurality of inverter circuits. In various embodiments the electrically powered vehicle further comprises a plurality of switches, each switch coupled in series between a respective battery of the plurality of batteries.

CROSS-REFERENCES TO OTHER APPLICATIONS

This application claims priority to U.S. provisional patent applicationSer. No. 62/969,232, for “POWER DISTRIBUTION CIRCUITS FOR VEHICLES WITHENERGY REGENERATION” filed on Feb. 3, 2020 which is hereby incorporatedby reference in entirety for all purposes.

This application is related to the following concurrently filed andcommonly assigned U.S. nonprovisional patent application Ser. No.17/165,565, for “REDUNDANT POWER DISTRIBUTION CIRCUITS INCLUDING DC/DCCONVERTERS” filed on Feb. 2, 2021, which is hereby incorporated byreference in its entirety for all purposes.

FIELD

The described embodiments relate generally to electrical circuits forrechargeable electric vehicles. More particularly, the presentembodiments relate to power distribution circuits that enableregenerative charging of batteries in electrically powered vehicles.

BACKGROUND

Currently there are a wide variety of electrically powered vehicles thatemploy multiple batteries for storing energy that is used forpropulsion. New electrical circuits are needed that enable regenerativecharging of the batteries while protecting the batteries from failureevents.

SUMMARY

In some embodiments an electrically powered vehicle comprises a DC busand a plurality of batteries, each coupled in parallel to the DC bus. Atleast one switch is coupled in series between at least one battery ofthe plurality of batteries and the DC bus and a plurality of invertercircuits are each coupled in parallel to the DC bus. A plurality ofmotors are each coupled to a respective inverter circuit of theplurality of inverter circuits. In various embodiments the electricallypowered vehicle further comprises a plurality of switches, each switchcoupled in series between a respective battery of the plurality ofbatteries.

In some embodiments the electrically powered vehicle comprises circuitrycoupled in series with each battery of the plurality of batteries andarranged to allow current to flow in one direction out of eachrespective battery of the plurality of batteries to the DC bus. Invarious embodiments the circuitry comprises at least one diode. In someembodiments each switch of the plurality of switches is arranged tobypass the circuitry coupled in series with each respective battery ofthe plurality of batteries. In various embodiments the electricallypowered vehicle further comprises a controller configured to detect afailed battery of the plurality of batteries and in response, open therespective switch of the plurality of switches to electrically isolatethe failed battery from the DC bus.

In some embodiments the electrically powered vehicle further comprises acontroller configured to detect a regeneration event and in responseclose the at least one switch to transfer power from the DC bus to atleast one battery of the plurality of batteries. In various embodimentseach of the plurality of inverter circuits is configured to generate amultiphase AC output used to drive one or more of the plurality ofmotors. In some embodiments each of the plurality of inverter circuitsis configured to generate a three-phase output. In some embodiments thethree-phase output generated by each of the plurality of invertercircuits operates between 0 to 400 Volts AC at a frequency between 0 and3 KHz. In various embodiments each of the plurality of motors is coupledto a respective propeller.

In some embodiments each of the plurality of motors is a synchronous ACpermanent magnet motor. In various embodiments the plurality of motorscomprises at least 12 motors.

In some embodiments a circuit comprises a plurality of batteries and aplurality of inverters with each coupled to a respective battery of theplurality of batteries and configured to generate a plurality of inputphases. A plurality of interphase transformers, each receiving one ormore of the plurality of input phases, generate a combined single drivephase. A motor is configured to receive the combined single drive phasefrom each of the plurality of interphase transformers. In variousembodiments at least one interphase transformer of the plurality ofinterphase transformers receives an input phase from each of theplurality of inverters.

In some embodiments each of the interphase transformers of the pluralityof interphase transformers receives an input phase from each of theplurality of inverters. In various embodiments each interphasetransformer of the plurality of interphase transformers electricallyisolates each of the plurality of input phases from each other. In someembodiments the circuit further comprises a controller configured tocontrol operation of at least one of the inverters to control a speedand a power of the motor. In various embodiments the controller isconfigured to detect a failed battery of the plurality of batteries andin response disable a respective inverter of the plurality of invertersthat is coupled to the failed battery.

In some embodiments one or more of the plurality of inverters areconfigured to charge one or more of the plurality of batteries when themotor generates electrical power during a regeneration event. In variousembodiments the motor is a synchronous AC permanent magnet motor. Insome embodiments the motor propels an electrically powered vehicle. Insome embodiments the motor is coupled to a propeller.

In some embodiments an electrically powered vehicle comprises aplurality of batteries and a plurality of inverters, each invertercoupled to a respective battery of the plurality of batteries andconfigured to generate a plurality of phases. A motor is configured toreceive each of the plurality of phases from each of the plurality ofinverters. In various embodiments each inverter of the plurality ofinverters is configured to generate three phases. In some embodimentsthe electrically powered vehicle further comprises a controllerconfigured to detect a failed battery and in response disable therespective inverter of the plurality of inverters that is coupled to thefailed battery.

In some embodiments the controller is configured to control the otherinverters of the plurality of inverters to continue operation of themotor with a reduced number of phases. In various embodiments one ormore of the plurality of inverters are configured to transmit power toone or more of the plurality of batteries when the motor generateselectrical power during a regeneration event. In some embodiments themotor is coupled to a propeller. In various embodiments the motor is asynchronous AC permanent magnet motor. In some embodiments theelectrically powered vehicle comprises at least 12 motors.

Numerous benefits are achieved by way of the present invention overconventional techniques. For example, embodiments of the presentinvention provide the ability to isolate a failure in the powerdistribution circuit from other components and to maintain powerdelivery to propulsion motors during a failure. Embodiments also enableregeneration events to recharge the batteries and the individual batterycircuits are isolated to prevent charge shuttling between batteries.These and other embodiments of the invention along with many of itsadvantages and features are described in more detail in conjunction withthe text below and attached figures.

To better understand the nature and advantages of the presentdisclosure, reference should be made to the following description andthe accompanying figures. It is to be understood, however, that each ofthe figures is provided for the purpose of illustration only and is notintended as a definition of the limits of the scope of the presentdisclosure. Also, as a general rule, and unless it is evident to thecontrary from the description, where elements in different figures useidentical reference numbers, the elements are generally either identicalor at least similar in function or purpose.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a schematic of a power distribution circuit includingprotection diodes and bypass switches, according to embodiments of thedisclosure;

FIG. 2 depicts a schematic of a power distribution circuit includingbreakers, according to embodiments of the disclosure;

FIG. 3 depicts a schematic of a power distribution circuit includinginverters and interphase transformers, according to embodiments of thedisclosure;

FIG. 4 depicts a schematic of a power distribution circuit includinginverters and a 12-phase motor, according to embodiments of thedisclosure;

FIG. 5 depicts a schematic of a power distribution circuit including DCto DC converters coupled to inverters via a DC bus, according toembodiments of the disclosure;

FIG. 6 depicts a schematic of a power distribution circuit including acommon power shaft driven by a plurality of motors, according toembodiments of the disclosure; and

FIG. 7 depicts an electrically powered aerial vehicle including a powerdistribution circuit, according to embodiments of the disclosure.

DETAILED DESCRIPTION

Techniques disclosed herein relate generally to electrical circuits forelectrically powered vehicles. More specifically, techniques disclosedherein relate to power distribution circuits for electrically poweredvehicles that include energy regeneration capability and redundantbattery systems. Various inventive embodiments are described herein,including methods, processes, systems, devices, and the like.

In order to better appreciate the features and aspects of powerdistribution circuits for electrically powered vehicles according to thepresent disclosure, further context for the disclosure is provided inthe following section by discussing one particular implementation of anelectrically powered vehicle according to embodiments of the presentdisclosure. These embodiments are for example only and other embodimentscan be employed in other electrically powered vehicles such as, but notlimited to automobiles, trains, busses, motorcycles and scooters.

FIG. 1 depicts a simplified schematic of a power distribution circuit100 for an electrically powered vehicle, according to embodiments of thedisclosure. As shown in FIG. 1, power distribution circuit 100 includesa plurality of separate batteries 105 a-105 c that can each include aplurality of cells. In one embodiment each battery 105 a-105 c producesa DC voltage of approximately 600 volts, however in other embodimentsthe batteries can produce a different voltage. Any number of batteriescan be used and some embodiments include between three and fifteenbatteries.

Each battery is coupled in parallel to a common DC bus 110 that iscoupled to a plurality of inverter circuits 115 a-115 c. Each invertercircuit 115 a-115 c is configured to generate a multiphase AC outputthat can be used to drive individual motors 120 a-120 c, which in oneembodiment can be synchronous AC permanent magnet type motors. In someembodiments each inverter circuit 115 a-115 c is configured to generatea three-phase output that operates between 0 to 400 Volts AC at afrequency between 0 and 3 kHz, however one of skill in the art willappreciate that other numbers of phases, output voltages, outputfrequencies and types of electrical motors can be used without departingfrom the invention.

As further shown in FIG. 1 a diode 125 a-125 c is coupled in-seriesbetween each respective battery 105 a-105 c and DC bus 110. Diodes 125a-125 c are oriented to allow batteries 105 a-105 c to provide currentto DC bus 110 and to block current flowing from the DC bus back to thebatteries. Such a configuration can be used to protect batteries 105a-105 c in the case of a battery that fails in a shorted condition,which would cause the other batteries to discharge current to the failedbattery. In further embodiments diodes 125 a-125 c can prevent chargeshuttling between batteries 105 a-105 c that is caused by each batteryhaving a different charge state. More specifically, in some embodimentseach battery 105 a-105 c can have a different age and/or chargecharacteristic such that batteries having a relatively higher level ofcharge will be blocked by diodes 125 a-125 c from back chargingbatteries that have a relatively lower level of charge. Such chargeshuttling can result in efficiency losses, heat generation and generalsystem instability.

To enable batteries 105 a-105 c to receive regenerative power generatedby motors 120 a-120 c, each circuit is equipped with a bypass switch 130a-130 c that selectively bypasses each respective diode 125 a-125 c.More specifically, when engaged, each respective bypass switch 130 a-130c enables power to be transferred from DC bus 110 to batteries 105 a-105c so the batteries can be recharged with power generated by motors 120a-120 c. In some embodiments bypass switches 130 a-130 c can be coupledto a controller 135 that monitors parameters of batteries 105 a-105 cand DC bus 110. Controller 135 can be configured to engage bypassswitches 130 a-130 c to bypass respective diodes 125 a-125 c when DC bus110 conditions (e.g., when a voltage level on the DC bus is higher thana voltage level of at least one of the batteries) indicate that aregenerative charging event is in process.

More specifically, in some embodiments motors 120 a-120 c are configuredto act as generators such that when the motors are rotated by externalmechanical forces, the motors generate electricity that travels backthrough inverter circuits 115 a-115 c and to DC bus 110. When thisoccurs, the voltage on DC bus 110 can increase above the voltage ofbatteries 105 a-105 c and controller 135 can detect this increase andrespond by closing one or more bypass switches 130 a-130 c allowingcurrent to flow from the DC bus to one or more of the batteries. Whenthe regenerative event ends, the voltage on DC bus 110 falls below thevoltage of batteries 105 a-105 c and controller 135 responds by openingthe bypass switches. In some embodiments controller 135 only enablesregenerative charging of batteries 105 a-105 c when a voltage of DC bus110 is above a threshold voltage, where the threshold voltage can be setbased on a maximum voltage of any one of the batteries such that chargeshuttling does not occur once the bypass switches are closed. In furtherembodiments, controller 135 can engage only one bypass switch at a time,or a subset of the bypass switches, to recharge individual batteries,which can be used in some embodiments for example, to “top off” anybattery that has a relatively low charge.

In further embodiments, one or more bypass switches 130 a-130 c can beengaged by an external circuit, such as when an operator specificallyengages a regenerative operation, such as descending in an airplane ordepressing a brake pedal, for example. In other embodiments controller130 can have logic circuitry that can selectively engage bypass switches130 a-130 c to recharge only those batteries 105 a-105 c that have acharge level below a particular threshold or to charge specificbatteries in a predetermined sequence to preserve their lifetime. One ofordinary skill in the art having the benefit of this disclosure, wouldrecognize many variations, modifications, and alternative techniques ofwhen and how to engage bypass switches 130 a-130 c.

In some embodiments bypass switches 130 a-130 c are electro-mechanicalrelay-type switches with metallic contacts that are engaged anddisengaged by an electromagnet. In other embodiments bypass switches 130a-130 c are solid-state and are made from silicon, gallium-nitride,silicon-carbide or other semiconductor material.

In some embodiments controller 135 can include fault monitoring anddetection circuitry such that during a regenerative operation when oneor more of bypass switches 130 a-130 c are closed if a fault is detected(e.g., a battery fails as a short) the bypass switch for that particularbattery 105 a-105 c is opened, preventing the other batteries fromdischarging current to the failed battery. One of ordinary skill, withthe benefit of this disclosure, would recognize many variations,modifications, and alternatives for using the bypass switches.

In some embodiments power distribution circuit 100 of FIG. 1 may beparticularly useful for aerial vehicles that need multiple separatebatteries 105 a-105 c for redundancy purposes. In such embodiments theisolated circuits inverter and motor circuits as shown in FIG. 1 canprovide additional redundancy and improved reliability. For example, theseparate inverter/motor and battery circuits would provide redundancy inthe case of an electrical short or failure in a DC supply line from onebattery to DC bus 110, for example. In some embodiments the location ofbypass switches 130 a-130 c may be proximate batteries 105 a-105 c (asshown in FIG. 1) while in other embodiments they may be proximateinverter circuits 115 a-115 c.

Batteries 105 a-105 c can be lead-acid, nickel-metal hydride,lithium-ion, lithium-ion polymer, alkaline or any other type of battery.Motors 120 a-120 c can be any type of AC motor including but not limitedto, brush, brushless, induction, or synchronous. Inverters 115 a-115 ccan by any type of analog or solid-state inverter circuit that convertsDC power to AC power. For simplicity, various active and passivecircuitry components are not shown in power distribution circuit 100.

FIG. 2 illustrates a power distribution circuit 200 that is similar topower distribution circuit 100 shown in FIG. 1, however this embodimentdoes not include diodes positioned between each battery and the DC bus.Instead, as shown in FIG. 2, breakers 230 a-230 c are positioned betweeneach battery 105 a-105 c and DC bus 110. During normal operationbreakers 230 a-230 c are in a closed position so DC power can flow frombatteries 105 a-105 c to DC bus 110, through inverter circuits 115 a-115c and to motors 120 a-120 c. Controller 235 is configured to detectsystem faults and in response it can open one or more of breakers 230a-230 c to prevent further failure, as described in more detail below.

In one example controller 235 is configured to detect the failure of abattery 105 a-105 c that fails in a shorted condition. Controller 235then commands breaker 230 a-230 c associated with that particularbattery 105 a-105 c to open, protecting the battery from receivingcurrent from the other batteries coupled to DC bus 110. During such afailure, controller 235 is configured to keep the other breakers 230a-230 c closed so that power can continue to be provided to motors 120a-120 c. In further embodiments controller 235 is configured to onlyopen breakers 230 a-230 c that are necessary and to keep all otherbreakers closed so power can continue to be supplied to motors 120 a-120c. This operating mode can be particularly useful for aerial vehicleswhere continuous uninterrupted operation of motors 120 a-120 c is animportant safety consideration.

In some embodiments breakers 230 a-230 c can be located proximatebatteries 105 a-105 c (as shown in FIG. 2) while in other embodimentsthey can be located proximate motors 120 a-120 c. In further embodimentsthere may be a set of breakers 230 a-230 c proximate each battery 105a-105 c and a separate set of breakers proximate each motor 120 a-120 c,the combination of which may be used to isolate failures in the wiringharness that extends from the batteries to the motors.

In some embodiments breakers 230 a-230 c are electro-mechanical typeswitches with metallic contacts. In other embodiments breakers 230 a-230c are solid-state and are made from silicon, gallium-nitride,silicon-carbide or other semiconductor material.

FIG. 3 illustrates a power distribution circuit 300 according toembodiments of the disclosure. As shown in FIG. 3, each battery 105a-105 d is coupled to a separate inverter 310 a-310 d that generates arespective three-phase AC output. There are also three separateinterphase transformers 315 a-315 c that each receive one input phasefrom each inverter 310 a-310 d and combine those inputs into onerespective drive phase 320 a-320 c that is coupled to a motor 330.Within each interphase transformer 315 a-315 c, each of the four phasedinputs are electrically isolated from each other so a failure in oneinput does not cause a failure in any of the other three inputs. In someembodiments each interphase transformer 315 a-315 c is configured toinductively combine the power delivered by each of its four respectiveinputs to generate a unified single drive phase 320 a-320 c for motor320.

Thus, each phase of motor 320 is driven by a respective interphasetransformer 315 a-315 c that receives approximately 25 percent of itspower from each of the four separate inverter/battery sets. When onebattery 105 a-105 d or inverter 310 a-310 d fails, each phase of motor330 will receive approximately 25 percent less power, but the motor willstill operate. In some embodiments a master controller (not shown inFIG. 3) can be used that controls each phase of each inverter 310 a-310c so the inputs to interphase transformers 315 a-315 c are synchronized.In some embodiments the motor controller circuit may include onlyinverters 310 a-310 d, while in other embodiments it can also includeinterphase transformers 315 a-315 c. Because of the electrical isolationbetween each circuit, charge shuttling between batteries 105 a-105 d isalso not a concern.

During a regenerative event when motor 330 is turned by externalmechanical forces, the motor delivers power to each interphasetransformer 315 a-315 c which then delivers power through the separateinverters 310 a-310 d back to batteries 105 a-105 d. Each battery 105a-105 d is isolated from each other battery so if one battery failspower from the other batteries cannot flow to the failed battery.Essentially each battery and each AC signal are isolated so eachoperates as an isolated system. As appreciated by one of skill in theart having the benefit of this disclosure the number of batteries, thenumber of inverters and the number of interphase transformers are notlimited to that shown in FIG. 3 and other embodiments can have adifferent number of these devices or configuration. For example, sixbatteries can be used with interphase transformers that each combine sixinputs. One of ordinary skill, with the benefit of this disclosure,would recognize many variations, modifications, and alternatives.

FIG. 4 illustrates a power distribution circuit 400 that is similar topower distribution circuit 300 illustrated in FIG. 3, however in thisembodiment there are no interphase transformers and the motor includestwelve separate windings. As shown in FIG. 4, there are four separatebatteries 105 a-105 d, each having a separate inverter 310 a-310 dcoupled thereto. Each inverter 310 a-310 d generates three separatephases with each phase being coupled directly to motor 405. Thus, withthe four, three phase inverters 310 a-310 d there are twelve phasesgenerated that are all individually coupled to motor 405.

In this embodiment, when one battery 105 a-105 d fails, three phases ofthe twelve phases in motor 405 will not receive power so the motor willstill operate, but at only approximately 75 percent of the power. Insome embodiments the circuit can include a controller configured tocontrol the other inverters (e.g., inverters that have not failed) ofthe plurality of inverters to continue operation of the motor with areduced number of phases. The controller can also control the invertercoupled to the failed battery to isolate the failed battery from thecircuit. Further, each battery 105 a-105 d and inverter 310 a-310 d areelectrically isolated from one another, so if a battery fails in ashorted state, current from the other batteries will not flow to thefailed battery. Essentially, each battery 105 a-105 d and inverter 310a-310 d set is electrically isolated from each other battery andinverter set. Because of the isolation, charge shuttling betweenbatteries 105 a-105 d is also not a concern.

During a regeneration event, rotational energy is applied to motor 405which operates as a generator, delivering current to each battery 105a-105 d through each respective inverter 310 a-310 d. In otherembodiments motor 405 can have any number of phases and inverters 310a-310 d can generate any number of phased outputs.

FIG. 5 illustrates a power distribution circuit 500 according toembodiments of the disclosure. Power distribution circuit 500 is similarto power distribution circuits 100 and 200 illustrated in FIGS. 1 and 2,respectively, that employ a DC bus, however the embodiment illustratedin FIG. 5 uses DC/DC converters in series with each battery to supplyenergy to the common DC bus. As shown in FIG. 5, individual batteries105 a-105 are each coupled to separate DC/DC converters 505 a-505 d thatconvert and regulate DC energy received from each respective battery toDC energy that is coupled to a common DC bus 510. DC bus 510 is coupledin parallel to a plurality of inverters 515 a-515 c that each generate athree-phase AC signal that drives individual motors 520 a-520 c.

Each DC/DC converter 505 a-505 d is configured to receive power fromonly it's respective battery 105 a-105 d and deliver regulated power toDC bus 510 based on the load applied to the DC bus. More specifically,in some embodiments each DC/DC converter 505 a-505 d can beindependently regulated and can use a voltage of DC bus 510 to controlthe amount of power the DC/DC converter extracts from its respectivebattery 105 a-105 d. In other embodiments a controller 525 can controleach DC/DC converter 505 a-505 d and cycle them on and off as needed toregulate the power delivered to DC bus 510. More specifically, eachDC/DC converter 505 a-505 d can run on a duty cycle where it is on for agiven period of time and off for a given period of time.

In this embodiment, if a battery 105 a-105 d fails the DC/DC converter505 a-505 d for that battery will not allow power to be transferred fromDC bus 510 to the failed battery (e.g., if the battery fails in ashorted condition). In one example each DC/DC converter 505 a-505 d (orthe controller 525) can monitor a voltage across each respective battery105 a-105 d to detect a short or failure within the battery and inresponse discontinue the transfer of power from that battery to DC bus510. In further embodiments, DC/DC converters 505 a-505 d can detectregenerative events and transfer power from DC bus 510 to batteries 105a-105 d for recharging. In some embodiments the respective DC/DCconverter 505 a-505 d can detect a regenerative event by monitoring avoltage potential on DC bus 510 as compared to the voltage available atthe respective battery 105 a-105 d. In some embodiments a thresholdvoltage may be used to engage regenerative charging when a voltage on DCbus 510 exceeds the threshold voltage.

In some embodiments DC/DC converters 505 a-505 d can adjust the loadsharing between each of the batteries 105 a-105 d to maintain eachbattery at a similar state of charge. In one embodiment each DC/DCconverter 505 a-505 d monitors the respective battery 105 a-105 dvoltage and a voltage on DC bus 510. If controller 525 senses a battery105 a-105 d voltage that is relatively higher than the other batteryvoltages, the controller can command the respective DC/DC converter 505a-505 d to draw more power from that battery to bring its charge statein line with the other batteries. In further embodiments each DC/DCconverter 505 a-505 d can receive the same PWM (pulse-width modulation)signal from controller 525 that controls the transfer of power from eachrespective battery 105 a-105 d to DC bus 510. In some embodiments, thesame PWM signal can “automatically” compensate for different chargelevels in batteries 105 a-105 d by transferring more power frombatteries having a relatively higher charge because of their highervoltage level and relatively less power from batteries having arelatively lower charge because of their lower voltage levels.

In some embodiments DC/DC converters 505 a-505 d can be placed proximatebatteries 105 a-105 d while in other embodiments they can be placedproximate motors 520 a-520 c. In further embodiments DC bus 510 can beeliminated and each DC/DC converter 505 a-505 d can be coupled to arespective inverter 515 a-515 c and each respective inverter can becoupled to a respective motor 520 a-520 c as shown in FIGS. 3 and 4.

In some embodiments DC/DC converters 505 a-505 d can be switch-modeconverters that are either isolated or non-isolated. In variousembodiments isolated DC/DC converters 505 a-505 d may be preferable toisolate the downstream circuitry from potential failures of batteries105 a-105 d. In some embodiments DC/DC converters 505 a-505 d can be,but are not limited to, the following architectures: step-down/buck,step-up boost, SEPIC, buck-boost or flyback. In further embodimentsDC/DC converter 505 a-505 d can employ one or more solid-state switchesthat can comprise, silicon, silicon-carbide, gallium-nitride or anyother type of solid-state switch.

FIG. 6 illustrates a power distribution circuit 600, according toembodiments of the disclosure. Power distribution circuit 600 is similarto the power distribution circuits disclosed in FIGS. 3 and 4 having onebattery coupled to each inverter, however in FIG. 6 each inverter powersredundant motors that are coupled to a single shaft. As shown in FIG. 6,three individual motors 605 a-605 c are coupled to a single propellershaft 610. Each of the three motors 605 a-605 c are driven by a separatebattery 105 a-105 c such that if one battery fails the remaining motorsand batteries are electrically isolated and can supply power topropeller shaft 610. When propeller 615 is rotated by externalmechanical forces during a regenerative event, each of the individualmotors 605 a-605 c generates electrical power that is fed back to eachrespective battery 105 a-105 c. If one battery 105 a-105 c or inverter310 a-310 c fails, propeller 615 will still be powered by the tworemaining motors 605 a-605 c, however with approximately 33% less power.In other embodiments fewer than three separate motors can be used pershaft and in some embodiments more than three motors can be used shaft.In yet further embodiments each motor 605 a can be supplied power via aredundant power distribution system such as illustrated in FIGS. 1-3 orFIG. 5.

FIG. 7 illustrates a simplified plan view of an aerial vehicle 700 inaccordance with embodiments of the disclosure. As shown in FIG. 7,aerial vehicle 700 includes twelve motors 705 a-7051 that are coupled toa battery pack 710 via a harness 715. Aerial vehicle 700 can use one ofor a combination of any of the power distribution circuits discussedabove and illustrated in FIGS. 1-6.

Although electric vehicle 700 is described and illustrated as oneparticular electric vehicle, embodiments of the disclosure are suitablefor use with a multiplicity of electronic vehicles. For example, anyelectrically powered vehicle that receives at least part of its powerfrom one or more batteries can be used with embodiments of thedisclosure. In some instances, embodiments of the disclosure areparticularly well suited for use with aerial vehicles because of thereliability and failure isolation of the power delivery circuits.Although a control circuit is not illustrated in each of circuits shownin FIGS. 1-6, one or more control circuits can be added to any of thecircuits described herein to control operation of the various componentsincluding, but not limited to, inverters, interphase transformers,switches, motors, feedback loops, etc.

For simplicity, various active and passive circuitry components are notshown in the figures. In the foregoing specification, embodiments of thedisclosure have been described with reference to numerous specificdetails that can vary from implementation to implementation. Thespecification and drawings are, accordingly, to be regarded in anillustrative rather than a restrictive sense. The sole and exclusiveindicator of the scope of the disclosure, and what is intended by theapplicants to be the scope of the disclosure, is the literal andequivalent scope of the set of claims that issue from this application,in the specific form in which such claims issue, including anysubsequent correction. The specific details of particular embodimentscan be combined in any suitable manner without departing from the spiritand scope of embodiments of the disclosure.

Additionally, spatially relative terms, such as “bottom or “top” and thelike can be used to describe an element and/or feature's relationship toanother element(s) and/or feature(s) as, for example, illustrated in thefigures. It will be understood that the spatially relative terms areintended to encompass different orientations of the device in use and/oroperation in addition to the orientation depicted in the figures. Forexample, if the device in the figures is turned over, elements describedas a “bottom” surface can then be oriented “above” other elements orfeatures. The device can be otherwise oriented (e.g., rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein interpreted accordingly.

Terms “and,” “or,” and “an/or,” as used herein, may include a variety ofmeanings that also is expected to depend at least in part upon thecontext in which such terms are used. Typically, “or” if used toassociate a list, such as A, B, or C, is intended to mean A, B, and C,here used in the inclusive sense, as well as A, B, or C, here used inthe exclusive sense. In addition, the term “one or more” as used hereinmay be used to describe any feature, structure, or characteristic in thesingular or may be used to describe some combination of features,structures, or characteristics. However, it should be noted that this ismerely an illustrative example and claimed subject matter is not limitedto this example. Furthermore, the term “at least one of” if used toassociate a list, such as A, B, or C, can be interpreted to mean anycombination of A, B, and/or C, such as A, B, C, AB, AC, BC, AA, AAB,ABC, AABBCCC, etc.

Reference throughout this specification to “one example,” “an example,”“certain examples,” or “exemplary implementation” means that aparticular feature, structure, or characteristic described in connectionwith the feature and/or example may be included in at least one featureand/or example of claimed subject matter. Thus, the appearances of thephrase “in one example,” “an example,” “in certain examples,” “incertain implementations,” or other like phrases in various placesthroughout this specification are not necessarily all referring to thesame feature, example, and/or limitation. Furthermore, the particularfeatures, structures, or characteristics may be combined in one or moreexamples and/or features.

1. An electrically powered vehicle comprising: a DC bus: a plurality ofbatteries, each coupled in parallel to the DC bus; at least one switchcoupled in series between at least one battery of the plurality ofbatteries and the DC bus; a plurality of inverter circuits, each coupledin parallel to the DC bus; and a plurality of motors, each coupled to arespective inverter circuit of the plurality of inverter circuits. 2.The electrically powered vehicle of claim 1 further comprising aplurality of switches, each switch coupled in series between arespective battery of the plurality of batteries.
 3. The electricallypowered vehicle of claim 2 further comprising circuitry coupled inseries with each battery of the plurality of batteries and arranged toallow current to flow in one direction out of each respective battery ofthe plurality of batteries to the DC bus.
 4. The electrically poweredvehicle of claim 3 wherein the circuitry comprises at least one diode.5. The electrically powered vehicle of claim 3 wherein each switch ofthe plurality of switches is arranged to bypass the circuitry coupled inseries with each respective battery of the plurality of batteries. 6.The electrically powered vehicle of claim 2 further comprising acontroller configured to detect a failed battery of the plurality ofbatteries and in response, open the respective switch of the pluralityof switches to electrically isolate the failed battery from the DC bus.7. The electrically powered vehicle of claim 1 further comprising acontroller configured to detect a regeneration event and in responseclose the at least one switch to transfer power from the DC bus to atleast one battery of the plurality of batteries.
 8. The electricallypowered vehicle of claim 1 wherein each of the plurality of invertercircuits is configured to generate a multiphase AC output used to driveone or more of the plurality of motors.
 9. The electrically poweredvehicle of claim 1 wherein each of the plurality of inverter circuits isconfigured to generate a three-phase output.
 10. The electricallypowered vehicle of claim 9 wherein the three-phase output generated byeach of the plurality of inverter circuits operates between 0 to 400Volts AC at a frequency between 0 and 3 KHz.
 11. The electricallypowered vehicle of claim 1 wherein each of the plurality of motors iscoupled to a respective propeller.
 12. The electrically powered vehicleof claim 1 wherein each of the plurality of motors is a synchronous ACpermanent magnet motor.
 13. The electrically powered vehicle of claim 11wherein the plurality of motors comprises at least 12 motors.
 13. Acircuit comprising: a plurality of batteries; a plurality of inverters,each coupled to a respective battery of the plurality of batteries andconfigured to generate a plurality of input phases; a plurality ofinterphase transformers, each receiving one or more of the plurality ofinput phases and generating a combined single drive phase; and a motorconfigured to receive the combined single drive phase from each of theplurality of interphase transformers.
 14. The circuit of claim 14wherein at least one interphase transformer of the plurality ofinterphase transformers receives an input phase from each of theplurality of inverters.
 15. The circuit of claim 14 wherein each of theinterphase transformers of the plurality of interphase transformersreceives an input phase from each of the plurality of inverters.
 16. Thecircuit of claim 13 14 wherein each interphase transformer of theplurality of interphase transformers electrically isolates each of theplurality of input phases from each other.
 17. The circuit of claim 1314 further comprising a controller configured to control operation of atleast one of the inverters to control a speed and a power of the motor.18. The circuit of claim 18 wherein the controller is configured todetect a failed battery of the plurality of batteries and in responsedisable a respective inverter of the plurality of inverters that iscoupled to the failed battery.
 20. The circuit of claim 14 wherein oneor more of the plurality of inverters are configured to charge one ormore of the plurality of batteries when the motor generates electricalpower during a regeneration event.
 19. The circuit of claim 14 whereinthe motor is a synchronous AC permanent magnet motor.
 20. The circuit ofclaim 14 wherein the motor propels an electrically powered vehicle. 21.The circuit of claim 14 wherein the motor is coupled to a propeller. 22.An electrically powered vehicle comprising: a plurality of batteries; aplurality of inverters, each coupled to a respective battery of theplurality of batteries and configured to generate a plurality of phases;and a motor configured to receive each of the plurality of phases fromeach of the plurality of inverters.
 23. The electrically powered vehicleof claim 24 wherein each inverter of the plurality of inverters isconfigured to generate three phases.
 24. The electrically poweredvehicle of claim 24 further comprising a controller configured to detecta failed battery and in response disable the respective inverter of theplurality of inverters that is coupled to the failed battery.
 25. Theelectrically powered vehicle of claim 26 wherein the controller isconfigured to control the other inverters of the plurality of invertersto continue operation of the motor with a reduced number of phases. 26.The electrically powered vehicle of claim 25 wherein one or more of theplurality of inverters are configured to transmit power to one or moreof the plurality of batteries when the motor generates electrical powerduring a regeneration event.
 27. The electrically powered vehicle ofclaim 25 wherein the motor is coupled to a propeller.
 30. Theelectrically powered vehicle of claim 26 wherein the motor is asynchronous AC permanent magnet motor.
 28. The electrically poweredvehicle of claim 26 comprising at least 12 motors.